We will investigate the antitumor effect of mimosine at molecular level, and try to see if there is any correlation between its antitumor effect and its inhibitory effect on PPT isozymes. Using antibody prepared against each form of PPT, we will study the rate of synthesis of PPT and try to elucidate the mechanism of enzyme inducation caused by glucagon or c-AMP. Furthermore, we will investigate if there is any alteration in enzyme induction in mice Hepatoma cells, B16 melanoma, or tumor-bearing animals.